Firefighters on the scene of explosion in Kenosha

What was believed to be a natural gas explosion leveled a vacant house in Kenosha, Wis., late Monday night, sending tornado-like debris and shock waves that damaged homes three blocks away.

"Everything flew off my walls," said Amanda Quiroz, who lives across the street from the blast site. "The walls kind of caved in and started cracking. I thought someone hit the house with a car."

Shattered glass flew over her children as they slept in their beds. "It could have killed my whole family," she said.

The explosion was felt at least three miles away.

As it was, no one was seriously injured, just "small scrapes, bumps and bruises due to shattered glass and individuals falling due to the shock waves of the explosion," said Kenosha Fire Chief John Thomsen.

The two-story house that was leveled at 55th Street and 22nd Avenue was owned by the city as part of a rehab program, Thomsen said. Preliminary investigation indicated a natural gas explosion, he said, and natural gas had been turned off in the area as a precaution.

When firefighters arrived in the shattered neighborhood shortly after 11:10 p.m., they found the home had been blown into small pieces, a small spot fire, and plywood and insulation hanging from tree branches as much as three blocks away, Thomsen said. Area residents reported large bay and picture windows blown out three to four blocks from the blast site. The explosion broke toilets, ripped exterior walls and dislodged kitchen cabinets.

Residents described what they initially thought was either a bomb or an earthquake.

Area resident Michael Dunnington, in an email message to the Tribune, said he and his downstairs neighbor used cardboard, blankets and duct tape to cover two bay windows of a neighbor that were completely shattered. "Houses in the immediate vicinity of the explosion received a lot of structural damage," he said.

As of 2:15 a.m., emergency crews were still on the scene searching the area.

Police called the situation secure, but firefighters and Wisconsin Energy were still investigating.